AC switch PFC with integrated charger and DC-DC for online UPS systems

A non-transitory computer-readable medium storing thereon sequences of computer-executable instructions for controlling an uninterruptible power supply (UPS) including an input configured to receive input AC power having an input AC voltage, a backup power input configured to be coupled to a backup power source and to provide DC power to the backup power source for charging, a positive DC bus, a negative DC bus, a converter coupled to the input, the backup power input, and the positive and negative DC busses, the converter including a first inductor, a second inductor, a first converter switch configured to couple the first inductor to a neutral connection, a second converter switch configured to couple the second inductor to the positive DC bus, and a third converter switch configured to couple the second inductor to the negative DC bus, the sequences of computer-executable instructions including instructions that instruct at least one processor to:

• operate, in a first mode of operation and during a positive half-cycle of the input AC voltage, the first converter switch to provide DC power derived from the input AC power to the positive DC bus via the first inductor and at least one of the second converter switch or the third converter switch to provide DC power derived from at least one of the positive DC bus or the negative DC bus to the backup power input through the second inductor;
• and
• operate, in the first mode of operation and during a negative half-cycle of the input AC voltage, the first converter switch to provide DC power derived from the input AC power to the negative DC bus via the first inductor and at least one of the second converter switch or the third converter switch to provide DC power derived from at least one of the positive DC bus or the negative DC bus to the backup power input through the second inductor.

A method of controlling an uninterruptible power supply (UPS) including an input configured to receive input AC power having an input AC voltage, a backup power input configured to be coupled to a backup power source and to provide DC power to the backup power source for charging, a positive DC bus, a negative DC bus, a converter coupled to the input, the backup power input, and the positive and negative DC busses, the converter including a first inductor, a second inductor, a first converter switch configured to couple the first inductor to a neutral connection, a second converter switch configured to couple the second inductor to the positive DC bus, and a third converter switch configured to couple the second inductor to the negative DC bus, the method comprising:

• operating, in a first mode of operation and during a positive half-cycle of the input AC voltage, the first converter switch to provide DC power derived from the input AC power to the positive DC bus via the first inductor and at least one of the second converter switch or the third converter switch to provide DC power derived from at least one of the positive DC bus or the negative DC bus to the backup power input through the second inductor;
• and
• operating, in the first mode of operation and during a negative half-cycle of the input AC voltage, the first converter switch to provide DC power derived from the input AC power to the negative DC bus via the first inductor and at least one of the second converter switch or the third converter switch to provide DC power derived from at least one of the positive DC bus or the negative DC bus to the backup power input through the second inductor.

An Uninterruptible Power Supply (UPS), the UPS comprising:

• an input configured to receive input AC power having an input AC voltage;
• a backup power input configured to be coupled to a backup power source and to provide DC power to the backup power source for charging;
• a positive DC bus and a negative DC bus, the positive and negative DC busses being galvanically coupled to the backup power input;
• and
• a converter coupled to the input, the backup power input, and the positive and negative DC busses, the converter including a first inductor, a second inductor, a first converter switch configured to couple the first inductor to a neutral connection, a second converter switch configured to couple the second inductor to the positive DC bus, and a third converter switch configured to couple the second inductor to the negative DC bus, wherein the UPS is voltage-frequency independent, and wherein the first converter switch is a bidirectional switch circuit including a first switch and a second switch coupled in series.